Fig. 3
From: Timeliness of contact tracing among flight passengers during the COVID-19 epidemic in Vietnam
Number of passengers needed to be traced, successfully traced, and not yet successfully traced* each day. *Number of passengers not yet successfully traced = number of passengers needed to be traced – number of passengers successfully traced. Number of passengers needed to be traced at each day = number of passengers not yet succesfully traced from previous day(s) + new number of passenger needed to be traced. Note: We excluded index cases and transited passengers from this analysis since we did not attempt to trace them